There’s a good reason why ClickBank is still a strong contender, however it does tend to focus more on digital products which may be of questionable quality. Yes, the review process is more professional these days, but it’s still primarily focused on selling digital products, especially “how to make money” courses and the like. That being said, there are some genuinely high-quality products on offer, and few affiliate programs are bigger than ClickBank, especially in selling (primarily digital) books.
Affiliate marketing overlaps with other Internet marketing methods to some degree, because affiliates often use regular advertising methods. Those methods include organic search engine optimization (SEO), paid search engine marketing (PPC – Pay Per Click), e-mail marketing, content marketing, and (in some sense) display advertising. On the other hand, affiliates sometimes use less orthodox techniques, such as publishing reviews of products or services offered by a partner.